It is often desirable to make assessment and/or predictions regarding the operation of a real world physical system, such as an electro-mechanical system. For example, it may be helpful to predict a Remaining Useful Life (“RUL”) of an electro-mechanical system, such as an aircraft body part, to help plan when the system should be inspected or repaired. Likewise, an owner or operator of a system might want to monitor a condition of the system, or a portion of the system, to help make maintenance decisions, budget predictions, etc. Even with improvements in sensor and computer technologies, however, accurately making such assessments and/or predictions can be a difficult task. For example, an event that occurs while a system is not operating might impact the RUL and/or condition of the system but not be taken into account by typical approaches to system assessment and/or prediction processes.
By way of example, consider a composite laminate structure, which might comprise layers of fibrous composite materials which can be joined to provide appropriate structural properties, such as in-plane stiffness, bending stiffness, strength, coefficient of thermal expansion, etc. The individual layers may comprise high-modulus, high-strength fibers (e.g., graphite, glass, boron, or silicon carbide) using polymeric, metallic, and/or ceramic matrix materials (e.g., epoxies, polyimides, aluminum, titanium, and alumina). Composite laminate structures are increasingly used in aircraft construction, and inadvertent damage to such structures, such as “delamination,” may represent an air safety concern (e.g., when the laminate structure is associated with a tail section of an airplane). As used herein, the term “delamination” may refer to a mode of failure for composite materials. In laminated materials, repeated cyclic stresses, impacts, etc. may cause layers to separate, which can form a mica-like structure of separate layers, with significant loss of mechanical toughness. Such delamination damage may impact the RUL of a system, require further investigation, etc. Note that delamination might not be noticeable by visual inspection, and detecting delamination damage can be a difficult process.
Moreover, in order to compute the RUL of a system, it may be necessary to know or assess a highly multi-dimensional state of a system. Note that the state of the system could change dramatically even when the system is not in operation (or is not operating in its most stressful mode). For example, an aircraft that is parked or taking on fuel, baggage, or passengers would not be expected to encounter as harsh an environment as it would during flight. There may be, however, cases where significant changes to an aircraft's health can occur during non-flight periods. For example, in at least one aircraft a pitch-up control cable was damaged while the controls were locked (and the plane was parked) because another aircraft taxied nearby resulting in exhaust that blasted the parked plane. This caused a force between 0.2 and 2.8 times the limit load on the pitch-up cable and even a single exposure was thought to be enough to break the cable. Another example may be associated with low speed collisions of a parked aircraft with a ground service equipment vehicle (such as a baggage delivery vehicle or a fuel truck). Ground service equipment interactions are responsible for most of the damage to commercial transport aircraft and it is estimated that half of the damage is due to collisions with baggage vehicles. These collisions may be associated with blunt impacts and may affect a significant area (and involve multiple elements hidden within the structure). Such collisions might leave no more than minimal visual signs of damage yet may still be deleterious to both aluminum and carbon-epoxy composite materials.
It would therefore be desirable to provide systems and methods to facilitate delamination assessments and/or predictions for a physical system in an automatic and accurate manner.